Low calorie burn w/ HRM

glittersoul
glittersoul Posts: 666 Member
in Fitness and Exercise
I'm becoming slightly frustrated with my recent HRM purchase. I bought a polar FT7 because all the reviews were great for them. I wanted it for motivation, to exercise more intensively and to keep track of my progress. I understand that HRM's aren't going to be fully accurate for calculating your calories burned and that I would have to live in a laboratory for them to be close to accurate but the numbers I'm getting really don't make sense. All my settings are correct and I have reset it 4 times.

For reference I weigh 325 lbs, 5'3" and 30 yrs old and Resting HR between 77 and 84 depending on the day. For the 30 Day Shred video i'm getting a burn of about 137 calories. A walk pushing my son in the stroller burns 78 cal's for 15 min. Walking/sitting around my house for 30 min not really doing much of anything burns only a few less calories than doing the 30 day shred videos. I did some experimenting with it last night sitting on the couch with the weight different. @125 lbs I burn 2 calories a min sitting there; @225 lbs/2 cal ; @325 lbs/2 cal ; @425/3 cal ; w/ my HR staying +/- 2 bpm difference.

I searched the net and the forums here extensively and have only found one person that had a problem similar to mine. She ended up sending it to polar to be checked out and they told her there wasn't anything wrong with it. So she got a different HRM all together and has had better results.

So... I am just wondering if there is something I am doing wrong. Or if I am delusional and this seems about right to everyone else. Or if I should get something different (and do you have recommendations)?

Thanks :)

Replies

  • rileysowner
    rileysowner Posts: 8,313 Member
    What sort of heart rates are you getting. The calorie calculations are based on the relationship between and elevated heart rate and calories burned, so if it is not registering your increased heart rate properly, your calories will be incorrect.
  • glittersoul
    glittersoul Posts: 666 Member
    I'm staying 70% - 80% (I think) 135 - 165 bpm during exercise. I know 30 day shred isn't the best example because my heart rate will drop from 150 to 114 because you are going from jumping jacks to laying on the floor for ab work so that brings the average down. During fast walks I get an avg of 144 max of 152. Just walking around the house it is about 96 to 115 or so.
  • rileysowner
    rileysowner Posts: 8,313 Member
    With those sort of numbers the calories burned should be higher. Not that underestimating calories is all that bad, but it can be discouraging it is still better than over estimating them in my opinion, especially if you eat your exercise calories back.
  • tross0924
    tross0924 Posts: 909 Member
    OK first HRM are not remotely accurate during non exercise. Walking around the house, sitting on the couch, throw away those numbers, they"re useless.

    Second let's look at the 15 minutes of walking with a heart rate average of 144 and 78 calories burned. According to this website

    http://www.sparkpeople.com/resource/calories_burned.asp

    walking at 2 miles an hour at your weight would burn 81 calories. If that's how fast your going then I'd say it's fairly accurate for that activity.

    Also, if it's a decent estimate then it's saying with an average heart rate of 144 you burn about 5 cals per minute. During the 30 day shred your average heart rate is going to be lower and your average burn per minute is about 4.5. Not really that far off there either.

    Honestly, you can get a different monitor, and get different numbers, they all use different calculations to get the totals. But it may be better to just use those numbers and keep at it. As you lose weight and get fitting you'll go faster and get better numbers.

    Good luck.
  • glittersoul
    glittersoul Posts: 666 Member
    Thanks for the quick reply. I agree that underestimating is way better and MFP certainly gives me some high numbers because of my size. I still like my HRM and find it fun to use. I guess I will just not pay attention the calories burned.
  • glittersoul
    glittersoul Posts: 666 Member
    For walks on my treadmill (its a manual w/ incline) I average 3.8 to 4.2 just walking. The walk in my example was outside about the same as I would do on my treadmill but on a flat surface. I'm not really sure how many mph's I walk but I try to keep up the pace untill I have to wait for cars to pass so I can cross the road.
  • mommy2josh
    mommy2josh Posts: 21
    your #'s sound just about right to me! with the HRM the higher your heart rate, the more cals you're going to burn. i will do 30 mins of my first video of billy blank tae bo, but my heart rate isn't staying in the zone it needs to, to burn more. I could lightly jog on the treadmill for the same amount of time and burn triple the amount of cals burned just by keeping my heart rate up.
  • WrenLynn
    WrenLynn Posts: 213
    I weigh 164 and depending on my intensity I will burn anywhere from 150 to 200 calories doing 30 Day Shred level one. It is only a twenty minute video so what more can you expect? Now at your weight I would think you would burn more but maybe you can't give it as much intensity yet and as you work up to it you will burn more. Also if you are not careful when you get down to do pushups and ab work your hrm may not be reading your heart rate at all thus the lower number.
  • glittersoul
    glittersoul Posts: 666 Member
    Thanks for the replies guys. It is only disappointing because my goal is to burn 500 - 1000 calories a day from exercise which seems super easy for a lot of other ppl my size with hrm's. I guess to reach my goal I will need to exercise about 5 hours a day.
  • glittersoul
    glittersoul Posts: 666 Member
    Updated for anyone else with similar issues to add that I found there were actually a lot more ppl w/ this problem. I understand it is a trivial thing. I'm not looking to eat more or get out of exercising that hard. Just it is motivating to me to see big numbers when I know I worked out hard. And I should burn more calories running in place or doing 30 day shred than I would sweeping the floor which according to my HRM i'm not. I will be calling polar to see what I can do about it and see if I can get the upgrade to this version. I will update this again for anyone that may come across this later after I get it fixed :)
  • smurfine78
    smurfine78 Posts: 3 Member
    I bumped into this old thread. I have exactly the same problem with my FT7. Yesterday I worked out for 56 minutes with an average heart rate at 136. I'm female and my weight is 61 kilos. It showed that I burned 400 calories, 120 calories less than my friends who has a different Polar watch. (We weigh almost the same). My old HRM (a different brand) also shows much more calories burned. I don't think the numbers on my FT7 are correct.
    What did you do with your HRM? I consider changing it into a Polar RCX3 instead. Is that a good choice?

    I also wonder if it shows gross or net calories? If my watch is correct and shows gross calories it means that my net calories is about 300 calories, and that seems low. I find it strange if it doesn't show net calories, because many people use it together with a dietary plan to see how many "bonus" calories you could eat.

  • ScubaSteve1962
    ScubaSteve1962 Posts: 609 Member
    smurfine78 wrote: »
    I bumped into this old thread. I have exactly the same problem with my FT7. Yesterday I worked out for 56 minutes with an average heart rate at 136. I'm female and my weight is 61 kilos. It showed that I burned 400 calories, 120 calories less than my friends who has a different Polar watch. (We weigh almost the same). My old HRM (a different brand) also shows much more calories burned. I don't think the numbers on my FT7 are correct.
    What did you do with your HRM? I consider changing it into a Polar RCX3 instead. Is that a good choice?

    I also wonder if it shows gross or net calories? If my watch is correct and shows gross calories it means that my net calories is about 300 calories, and that seems low. I find it strange if it doesn't show net calories, because many people use it together with a dietary plan to see how many "bonus" calories you could eat.

    Which one does your friend have? If she can do the fitness test, it would make a difference. The RCX3 is a good choice, or the M400 activity monitor. Not sure about the gross or net, but they are designed to give you your total calorie burn during exercising, assuming that your daily activity will stay the same.
  • smurfine78
    smurfine78 Posts: 3 Member
    She has a RCX3 and i changed my into a RCX3 as well today

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